The results herein achieved allow to provide practical recommendations for the EF walls idealization.
The critical comparison between FE and EF solutions is made in terms of (i) pushover curves, (ii) damage patterns, (iii) generalized forces, and (iv) drift values at scale of single elements. The investigated irregularity deals with the presence of openings with different height at the same storey or the presence of small openings. Continuum finite element (FE)-based numerical solutions are considered as reference to assess the reliability of EF approach for a number of irregular masonry walls case studies. This constitutes the first main issue within the EF idealization of walls. the elements in charge of resisting the horizontal and vertical loads. This paper aims to investigate the reliability of four existing rules for the a priori identification of the geometry of the piers, i.e.
Such rules are typically applied a priori and they can strongly affect the seismic response. However, the definition of modelling rules for the EF idealization of walls is not always straightforward. Within the framework of modelling of unreinforced masonry structures, the equivalent frame (EF) approach is widely used for the seismic assessment. These walls have been modelled with a hybrid equivalent frame model which consists of mono-dimensional beam-like element for piers, fully rigid offsets for the nodal panels and a strut and tie scheme for spandrels. The proposed schematization has been used to simulate the seismic behavior of some reference case studies of existing masonry walls, strengthened with different steel ties arrangement. Moreover, the local failures of both compressed masonry and/or tensile-resistant elements are better identified and, consequently, also the failure mechanisms of the whole equivalent frame are better detailed. Such model allows a more realistic representation of the mechanical behavior of spandrels because both amount of axial force within the spandrel and the reduced elastic flexural and shear stiffness due to progressive cracking of material are taken into account. In this paper an alternative strut and tie scheme to model the spandrel panels, suitable to be used within the equivalent frame approach, is presented: the compressed masonry material is schematized with an equivalent diagonal no-tension truss, whose length and effective compressed area are obtained with limit equilibrium conditions, while tensile-resistant element is represented by no-compression truss. Actually, horizontal mono-dimensional beam-like elements provided of both strength and displacement capacity are used to schematize the spandrel panels, also according with the most of current national and international codes. Among these, modeling of spandrel panels plays a key role to correctly analyze the in-plane seismic response of unreinforced masonry walls. The equivalent frame model is the most used approach to analyze the seismic behavior of both existing and new masonry constructions but, despite this, several aspects are being researched to improve its effectiveness. Modeling of masonry buildings subjected to seismic actions still represents an open problem in structural engineering. It is shown that use of the EF method enabled prediction of the seismic response of the two case-study clay brick URM buildings with a high level of accuracy. The effect of diaphragm stiffness on the global response of the two case-study buildings was also studied. Static and dynamic nonlinear analyses were undertaken by applying the equivalent frame (EF) approach, and time-history records attained during the Canterbury earthquake sequence were used to conduct dynamic analyses and facilitate direct comparison to observed building damage.
#Simulation guso professional#
To address this deficiency and provide a novel evidence base for use of the procedure by the professional structural engineering community, modelling of the seismic response of two unreinforced clay brick masonry buildings that were damaged during the 2010/2011 Canterbury earthquake sequence is reported.
While the equivalent frame (EF) approach for modelling the in-plane seismic response of URM buildings is gaining popularity, particularly in Mediterranean countries, the procedure is currently relatively unknown elsewhere and the validity of the procedure when applied to simple and prevalent New World clay brick URM construction has not yet been demonstrated in a meaningful way. In New World colonial countries and territories such as Australia, New Zealand, and the West Coast of North America, the predominant form of unreinforced masonry (URM) construction is relatively modest one or two storey buildings composed of clay brick masonry.
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